Messages in this thread | | | From | Rob Clark <> | Date | Sun, 4 Oct 2020 17:10:47 -0700 | Subject | Re: [PATCH 04/14] drm/msm: Add priv->mm_lock to protect active/inactive lists |
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On Sun, Oct 4, 2020 at 3:15 PM Daniel Vetter <daniel@ffwll.ch> wrote: > > On Sun, Oct 4, 2020 at 9:21 PM Rob Clark <robdclark@gmail.com> wrote: > > > > From: Rob Clark <robdclark@chromium.org> > > > > Rather than relying on the big dev->struct_mutex hammer, introduce a > > more specific lock for protecting the bo lists. > > > > Signed-off-by: Rob Clark <robdclark@chromium.org> > > --- > > drivers/gpu/drm/msm/msm_debugfs.c | 7 +++++++ > > drivers/gpu/drm/msm/msm_drv.c | 1 + > > drivers/gpu/drm/msm/msm_drv.h | 13 +++++++++++- > > drivers/gpu/drm/msm/msm_gem.c | 28 +++++++++++++++----------- > > drivers/gpu/drm/msm/msm_gem_shrinker.c | 12 +++++++++++ > > drivers/gpu/drm/msm/msm_gpu.h | 5 ++++- > > 6 files changed, 52 insertions(+), 14 deletions(-) > > > > diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c > > index ee2e270f464c..64afbed89821 100644 > > --- a/drivers/gpu/drm/msm/msm_debugfs.c > > +++ b/drivers/gpu/drm/msm/msm_debugfs.c > > @@ -112,6 +112,11 @@ static int msm_gem_show(struct drm_device *dev, struct seq_file *m) > > { > > struct msm_drm_private *priv = dev->dev_private; > > struct msm_gpu *gpu = priv->gpu; > > + int ret; > > + > > + ret = mutex_lock_interruptible(&priv->mm_lock); > > + if (ret) > > + return ret; > > > > if (gpu) { > > seq_printf(m, "Active Objects (%s):\n", gpu->name); > > @@ -121,6 +126,8 @@ static int msm_gem_show(struct drm_device *dev, struct seq_file *m) > > seq_printf(m, "Inactive Objects:\n"); > > msm_gem_describe_objects(&priv->inactive_list, m); > > > > + mutex_unlock(&priv->mm_lock); > > + > > return 0; > > } > > > > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c > > index 49685571dc0e..dc6efc089285 100644 > > --- a/drivers/gpu/drm/msm/msm_drv.c > > +++ b/drivers/gpu/drm/msm/msm_drv.c > > @@ -441,6 +441,7 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv) > > init_llist_head(&priv->free_list); > > > > INIT_LIST_HEAD(&priv->inactive_list); > > + mutex_init(&priv->mm_lock); > > I highly recommend you drop a > > fs_reclaim_acquire(GFP_KERNEL); > might_lock(&priv->mm_lock); > fs_reclaim_release(GFP_KERNEL); > > in here to teach lockdep about your ordering against the shrinker. > Gives you full testing every boot, even if your shrinker never gets > called.
Good idea..
(tbf, I have tested this with android+lockdep which pretty is great shrinker exercise.. but immediate notification of future problems is a good plan)
BR, -R
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